Fans are commonly used to increase comfort by moving air and improving ventilation. Fans have been used in residential, institutional, and commercial facilities for many years and are manufactured by a number of companies worldwide. Those who have observed ceiling fans after some period of use recall the collection of dust and other airborne particulate matter on the fan blades, especially the leading edge. Even in what is normally thought to be a clean environment, such as a residence, there is considerable airborne matter that collects while the fan is operating.
There exist a number of patents teaching the use of filters, or filter fasteners, blade covers or specifically designed blades to modify fans and/or their blades for capturing pollutants or foreign matter. For example, U.S. Pat. No. 6,174,340 shows a room air filter apparatus including a multi-sided housing having longitudinally spaced first and second ends, a plurality of sides between the first and second ends, and a plenum inside the housing. Each of the sides has an empty space frame by outer edges of the housing side. A fan is mounted to the housing and is operably disposed, preferably, within the plenum to draw air from the plenum and to exhaust the air outside of the housing. Filter panels are removably attached to the outer surfaces of the edges and filter material is mounted in the panels to cover the empty spaces. Magnets mounted on edges of the panels may be used as attachment devices as well as other devices for clipping the panels onto the outer surfaces of the edges of the housing. The filter material is preferably a self-charging electrostatic washable material.
U.S. Pat. No. 5,912,369 illustrates self-adhesive fibrous air filters that are universally compatible with devices that require filtered air and devices that provide filtered air. The self-adhesive air filters are fabricated from a flexible fibrous air filter blank composed of, for example, polyester batting, that is coated with an air permeable non-drying adhesive that has been vacuumed into the interstices of the fibers. A template serves as a protective cover for the non-drying adhesive and enables a user to shape and/or size the blank to configurations that are compatible with the air intake regions of the devices on which the self-adhesive air filters are to be installed.
U.S. Pat. No. 5,795,131 discloses a ceiling fan for cleaning air in a room wherein each blade of the ceiling fan has a cavity open to the top and bottom surfaces of each fan blade and a filter unit in each of the cavities but within the confines of the fan blade such that, when the ceiling fan is operated, the airflow created by the ceiling fan will be forced through the filter unit from the bottom surface through to the top surface, wherein the filter units can collect airborne particles.
U.S. Pat. No. 5,591,006 comprises a removable, washable decorative cover for each thin, flat fan blade of a paddle-type ceiling fan. The decorative cover includes a main sleeve of uninterrupted tubular shape, each end of which is open, and formed of highly elastic and expandable decorative fabric, preferably SPANDEX. The main sleeve is of sufficient elastic strength and sized substantially smaller in width than the width of the fan blade whereby, when mounted over a preselected main portion in length of the fan blade, the gripping action of the elastically stretched fabric conformingly against the surface of the main portion of the fan blade is sufficient to prevent movement therebetween when the ceiling fan is in operation. The cover may also include an end sleeve formed of the same elastic fabric and transverse width, one end of which is open, the other end of which is closed. The end sleeve conformingly fits over the distal end of the fan blade in either spaced, abutting or overlapping orientation on the distal portion of the fan blade with respect to one open end of the main sleeve. The end sleeve is likewise of sufficient elastic strength, when stretched to cover the distal portion of the fan blade, to remain stationary on the distal end of the fan blade during ceiling fan operation.
U.S. Pat. No. 5,562,412 consists of a fan apparatus with a filter affixed to one or more of its fan blades such that the rotating fan blades carry the filter or filters through a medium to extract pollutants.
U.S. Pat. No. 5,370,721 describes a ceiling fan filter for filtering the air in a room having a ceiling fan. The ceiling fan filter is made from at least one layer of resilient polymeric fiber filter material. Each layer has a length, a width, an upper surface, a lower surface and two side edges which extend along the length of the layer. A narrow compressed strip is formed in the filter material by compressing and heating the layer of filter material so that the filter material is fused together. The compressed strip causes an expanded thickness of the side edges to increase the effective filter surface area of the filter and gives the filter a semicircular cross-sectional shape perpendicular to the length of the filter. An adhesive layer is joined to the lower surface of the filter to attach the filter to the fan blade of a ceiling fan.
U.S. Pat. No. 4,676,721 depicts a method and device for reducing the pollution of the air in a room equipped with a ceiling fan having one or more rotating blades comprising covering at least one blade of the fan with porous dust-absorbent material whereby movement of the fan blades removes pollution from the room air.
The above cited inventions are relatively cumbersome to use and maintain, or impractical for use especially in residential locations. None of these inventions effectively deal with the problem of improving air quality while operating the fan and having a means of inexpensively and conveniently renewing the pollutant and particulate matter adsorption surface.